The present invention relates to computer software utility programs, and more specifically to selection of a projection plane in computer aided design and computer aided manufacture (CAD/CAM) software systems.
While using CAD/CAM applications it is often desirable to produce two dimensional (2-D) plans representing different views of a three dimensional (3-D) model. Production of 2-D views from the 3-D model can be referred to as generative drafting. One of the difficulties attaching to the generative drafting process is the choice of the most desirable orientations for the drafting views.
In some currently available systems, the selection of the projection plane can be made only on the 3-D model. If a user wishes to change the projection plane, he must revert back to the 3-D model and the system must recompute the 2-D views. Re-computation can take valuable computing time and lead to a loss of productivity. Other systems have included a specific 3-D viewer containing various manipulation commands to avoid this loss of productivity. However, use of the 3-D viewer can also slow down productivity as the user must call the viewer on the screen each time he wants to manipulate the orientation of a projected view.
Other known systems display, by default in the drawing plane, an isometric view of the 3-D model. A user must then define an orientation by the selection of two planes, or edges, with a name of a view he wants to obtain. When the last selection is made, the projection can be computed by the system. Any change in the parameters selected by the user requires the system to generate another projection computation. Such computations can be processor intensive and time consuming.
There is therefore a need for an easy-to-use manipulator which can allow a user to proceed with desired manipulations while staying in the drawing document and to visualize the results of a change of orientation before entering the projection creation command.